The question of an Oswald imposter was also raised in an FBI letterhead memorandum to the Secret Service dated November 23, 1963. It was based in part upon information received by CIA headquarters on October 9, 1963, that on October 1, 1963, Oswald had contacted the Soviet Embassy in Mexico City:

The Central Intelligence Agency advised that on October 1, 1963, an extremely sensitive source had reported that an individual identified himself as Lee Oswald, who contacted the Soviet Embassy in Mexico City inquiring as to any messages. Special Agents of this Bureau, who have conversed with Oswald in Dallas, Tex., have observed photographs of the individual referred to above and have listened to a recording of his voice. These Special Agents are of the opinion that the above-referred-to individual was not Lee Harvey Oswald.

In response to a committee inquiry, the FBI reported that no tape recording of Oswald's voice was in fact ever received. The Bureau explained that its Dallas office only received the report of a conversation to which Oswald had been a party. This explanation was independently confirmed by the committee. A review of relevant FBI cable traffic established that at 7:23 p.m. (CST) on November 23, 1963, Dallas Special Agent-in-Charge Shanklin advised Director Hoover that only a report of this conversation was available, not an actual tape recording. On November 25, the Dallas office again apprised the Director that "[t]here appears to be some confusion in that no tapes were taken to Dallas * * * [O]nly typewritten [reports were] supplied * * *."

Shanklin stated in a committee interview that no recording was ever received by FBI officials in Dallas. Moreover, former FBI Special Agents James Hosty, John W. Fain, Burnett Tom Carter, and Arnold J. Brown, each of whom had conversed with Oswald at one time, informed the committee they had never listened to a recording of Oswald's voice.

Finally, on the basis of an extensive file review and detailed testimony by present and former CIA officials and employees, the committee determined that CIA headquarters never received a recording of Oswald's voice. The committee concluded, therefore, that the information in the November 23, 1963, letterhead memorandum was mistaken and did not provide a basis for concluding that there had been an Oswald imposter.